the "dir /b /d /n /s /x *.xls > files.csv" line, will, if entered at a
command prompt, list all of the .xls files from the current directory and
every sub-directory in the tree below it - so if you run it in the root
directory of C: (ie: C:\>dir /b /d /n /s /x *.xls > files.csv) it will list
every xls file on your c: hard disk
If the problem is that you dont understand the use of command prompt and
"dir" command in the first place then I suggest you go down the route of
using a macro instead.
you can find a 'make your own' at ozgrid - run by one of the MVP from here
http://www.ozgrid.com/forum/showthread.php?t=51306
or download a pre-packaged one
http://www.vbaexpress.com/kb/getarticle.php?kb_id=837
hth
Regards
RegMigrant